eutrophication & hypoxia/ FlickrUC Santa Cruz prof cleans the air while repairing the ocean.
When it comes to the climate, a California researcher may have just killed two birds with one stone – in an eco-friendly kind of way.
Greg Rau, a scientist at UC Santa Cruz and Lawrence Livermore National Laboratory, has found that seawater and calcium can be used to remove carbon dioxide from gas-fired plant emissions.
But even better, he found that when that mixture is combined with limestone and pumped back into the ocean, the mix can reduce ocean acidification – benefiting marine life and habitat.
“This approach not only mitigates CO2, but also potentially treats the effects of ocean acidification,” Rau told E&E publishing.
Carbon dioxide not only has been linked to global warming, but increasing acidity in the ocean. Research has shown the increase in acidity is harmful to marine life.
Many coal and oil plants already use limestone “scrubbers.”
In a limestone wet scrubber, limestone is suspended in water. Gas emitted by the power plant flows through the slurry where it reacts with, or in a sense is trapped, by the scrubber.
In this experiment, gas emitted by a natural gas plant reacted with Rau's calcium, seawater and limestone scrubber to form calcium bicarbonate.
Calcium bicarbonate is alkaline, or basic – the opposite of acidic. So, putting it in the ocean will reduce the seawater's acidity.
"The experiment in effect mimics and speeds up nature's own process," Rau said in a statement. "Given enough time, carbonate mineral (limestone) weathering will naturally consume most anthropogenic CO2. Why not speed this up where it's cost effective to do so?"
Rau’s experiments showed that his scrubbers could remove up to 97 percent of the carbon dioxide released by the gas plant.
His study is published in the journal Environmental Science and Technology.